package server;

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    /**
     * 定义socket监听的端口号
     */
    private int port = 8080;

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }


    /**
     * Minicat启动需要初始化展开的一些操作
     */
    public void start() throws Exception {

        // 加载解析相关的配置，web.xml
        loadServlet();


        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize = 50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();


        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                corePoolSize,
                maximumPoolSize,
                keepAliveTime,
                unit,
                workQueue,
                threadFactory,
                handler
        );





        /*
            完成Minicat 1.0版本
            需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
         */
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        /*while(true) {
            Socket socket = serverSocket.accept();
            // 有了socket，接收到请求，获取输出流
            OutputStream outputStream = socket.getOutputStream();
            String data = "Hello Minicat!";
            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
            outputStream.write(responseText.getBytes());
            socket.close();
        }*/


        /**
         * 完成Minicat 2.0版本
         * 需求：封装Request和Response对象，返回html静态资源文件
         */
        /*while (true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            response.outputHtml(request.getUrl());
            socket.close();

        }*/


        /**
         * 完成Minicat 3.0版本
         * 需求：可以请求动态资源（Servlet）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            // 静态资源处理
            if(servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            }else{
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request,response);
            }

            socket.close();

        }
*/

        /*
            多线程改造（不使用线程池）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }*/


        //System.out.println("=========>>>>>>使用线程池进行多线程改造");
        /**
         * 多线程改造（使用线程池）
         */
        while (true) {

            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket, servletMap);
            //requestProcessor.start();
            threadPoolExecutor.execute(requestProcessor);
        }


    }


    private Map<String, HttpServlet> servletMap = new HashMap<String, HttpServlet>();

    /**
     * 加载解析web.xml，初始化Servlet
     */
    private void loadServlet() throws Exception {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("server.xml");
        SAXReader saxReader = new SAXReader();
        Document document = saxReader.read(resourceAsStream);
        Element rootElement = document.getRootElement();
        List<Element> selectNodes = rootElement.selectNodes("//Host");
        if (!(selectNodes.size() > 0)) {
            return;
        }
        Attribute appBase = selectNodes.get(0).attribute("appBase");
        String absolutePath = appBase.getText();
        File directory = new File("../");// 参数为空
        String courseFile = directory.getCanonicalPath();
        ArrayList<File> files = FindFile.getListFiles(courseFile + absolutePath, "web.xml");
        for (File file : files) {
            resourceAsStream = new FileInputStream(file);
            saxReader = new SAXReader();
            try {
                document = saxReader.read(resourceAsStream);
                rootElement = document.getRootElement();

                selectNodes = rootElement.selectNodes("//servlet");
                for (Element element : selectNodes) {
                    // <servlet-name>lagou</servlet-name>
                    Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                    String servletName = servletnameElement.getStringValue();
                    // <servlet-class>server.LagouServlet</servlet-class>
                    Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                    String servletClass = servletclassElement.getStringValue();
                    // 根据servlet-name的值找到url-pattern
                    Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                    // /lagou
                    String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
                    HttpServlet httpServlet;
                    try {
                        httpServlet = (HttpServlet) Class.forName(servletClass).newInstance();
                        servletMap.put(urlPattern, httpServlet);
                    } catch (Exception e) {
                        String path = file.getAbsolutePath();
                        if (!path.contains("target")) {
                            path = path.substring(
                                    0, path.lastIndexOf("\\src")
                            ) + "\\target\\classes\\" + servletClass.replaceAll("\\.", "\\\\");
                        } else {
                            path = path.substring(0, path.lastIndexOf("\\")) + "\\"
                                    + servletClass.replaceAll("\\.", "\\\\");
                        }
                        var clazz = findClass(path.substring(0, path.lastIndexOf("\\")),
                                servletClass.substring(servletClass.indexOf(".") + 1));
                        if (clazz != null) {
                            httpServlet = (HttpServlet) clazz.newInstance();
                            servletMap.put(urlPattern, httpServlet);
                        }
                    }
                }
            } catch (DocumentException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (InstantiationException e) {
                e.printStackTrace();
            }
        }
        //InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("web.xml");
        System.out.println(servletMap.toString());
    }


    /**
     * Minicat 的程序启动入口
     *
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            // 启动Minicat
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static Class findClass(String classPath, String className) {
        ClassLoader systemClassLoader = ClassLoader.getSystemClassLoader();
        //获取路径classes的路径
        String prefix = classPath.substring(0, classPath.indexOf("classes") + 8);
        //这里得到的就是com.company.base.controller包的全名
        String packageName = classPath.substring(classPath.indexOf("classes") + 8).replaceAll("/", ".");
        try {
            URL classes = new URL("file:///" + prefix);
            ClassLoader custom =
                    new URLClassLoader(new URL[]{classes}, systemClassLoader);
            Class<?> clazz = custom.loadClass(packageName + "." + className);
            return clazz;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}
